Japanese Patent Laying-Open No. 04-295202 discloses an electric motor drive and power processing apparatus used in electrically powered vehicles. The electric motor drive and power processing system includes a secondary battery, inverters IA, IB, induction motors MA, MB, and a control unit. Induction motors MA, MB include respective windings CA, CB in a Y configuration, and windings CA, CB have neutral nodes NA, NB connected via an EMI filter to an input/output port.
Inverters IA, IB are provided correspondingly to induction motors MA, MB respectively and connected respectively to windings CA, CB. Further, inverters IA, IB are connected in parallel with the secondary battery.
In the electric motor drive and power processing apparatus, inverters IA, IB can generate sinusoidal and regulated AC power across neutral points NA, NB, and supply the generated AC power to external devices connected to the input/output port.
The electric motor drive and power processing system disclosed in Japanese Patent Laying-Open No. 04-295202 is useful in that it has the power supply capability to generate AC power and supply the generated AC power to external devices. Japanese Patent Laying-Open No. 04-295202, however, does not particularly consider an electric power supply system that provides a reverse flow of its generated AC power to a commercial electric power system and that totally manages electric power supply from a plurality of vehicles connected to the commercial electric power system.